How often do you use it? Once a week, once a month....other frequencies? I've read before that if a Lion battery is to be maintained without being used for awhile, it likes to be at about an 80% charge. I would drain it to 80% and take it out of the computer all together if you don't use it but once or twice a month...Re-insert it when you use your Thinkpad...or if you only use with AC power, then don't insert it. Just check your battery and charge it to 100% when you do, about once a month and let it drain back to 80% again before re-storing it....Also, occassionally these batteries like to be drained down to the point of the computer giving the signal that they will be turning off. Maybe every other month you should do this...but re-store at 80%...just my opinion.